In vitro antibacterial potential of some Vitex species against human pathogenic bacteria

OBJECTIVE: To study the antibacterial activity of the leaf methanol extracts of five different species of Vitex namely, Vitex altissima (V. altissima), Vitex diversifolia (V. diversifolia), Vitex negundo (V. negundo), Vitex peduncularis (V. peduncularis) and Vitex trifolia (V. trifolia). METHODS: Antibacterial assay was carried out by using disc diffusion method, determination of minimum inhibitory concentrations (MIC) and minimum bactericidal concentrations (MBC) against five strains of Gram-positive and seven strains of Gram-negative human pathogenic bacterial strains. RESULTS: The results of antibacterial activity of Vitex species showed that the extracts possessed a broad spectrum of antibacterial activity. The V. peduncularis possessed the highest activity against all the microorganisms screened. It produced a zone of inhibition ranged between (11.000 ± 0.577) and (22.670 ± 0.667) mm and the MIC values were from 62.5 to 1 000.0 μg/mL and the MBC values were from 125.0 to 2 000.0 μg/mL. CONCLUSIONS: Based on the present study, V. peduncularis is recommended for the isolation of antibacterial molecule responsible for the activity against the tested human pathogenic bacterial strains.